Device for grinding pulpy semifluid materials and mixtures



Jan. 12, 1932. K. ALBERT 1,840,827

DEVICE FOR GRINDING PULPY SEMIFLUID MATERIALS AND MIXTURES Filed Nov. 9, 1928 '10 operating the same.

Patented Jan. 12, 1932' A,

. UNITED STATES KARL ALBERT, OF VIENNA, AUSTRIA.

DEVICE FOR GRINDING fiULPY SEKIFLUID MATERIALS AND MIXTURES Application-filed November 9, 1928, Serial No. 318,248, and in Austria February 25, 1928.

The well known devices for grinding pulpy semi-fluid materials and mixtures, for mstance paints, in the various stages of their preparation, victuals, such as chocolate and 5 pharmaceutical products, f. i. tooth paste,

are all showing the drawback that their working capacity or efliciency is relatively very small compared with the weight of the grinding apparatus and the energy required for The semi-fluid mixture being tough and often sticky, will in many cases cover and clog a larger or smaller portion of the grinding surfaces and thereby render the same inefficient. In consequence thereof the grinding surface is working not uniformly and wearing irregularly, whilst the frictional losses of the machine remain the same and will be of a considerable amount in view of the reduced output. Furthermore it is also necessary to have the grinding apparatus cleaned very frequently. Owing to these drawbacks the surface grinding machines have been abandoned and been nearly completely substituted by the more expensive devices with grinding rollers or cylinders which also have a small working capacity, when compared with the machine according to my invention, but which are less subject to disturbances. The invention relates to a method by which the above-mentioned drawbacks are overcome and the working capacity of grinding devices is considerably increased. 'In' consequence and for fully utilizing this increased capacity 35 of working, it appears advantageous to provide the grinding devices working according to this method with several special appliances The advantages of the method are particu lar-' ly obvious with surface grinding machines 40 having in general a conical grinding surface. The new method consists therein that the pulp semi-fluid mass to be minced in the grin g device does'not flow to the; grinding surfaces under the influence of its own weight,

but that it is supplied to the said i'lrlinding surfaces while pressure is applied. 's may either be done by conveying the whole mass under pressure mto the grinding device for which urpose the mass-is allowedto pass throug a pressure generating installation f. i. a pump or a press; a diiferent method of operation consists in applying pressure to another medium which transmits the pressure on to the goods to be ground. In the sim lest case this medium is air or a gas selecte according to the character of the goods under treatment. In special cases, however, a liquid may also be used as pressure transmitting medium which must, however, not mix with the goods nor influence the same in any way. In these cases only the pressure medium and not the goods to be ground need passthrough the pressure generatingdevice'.

Besides increasing the working capacity of the grinding device this process offers the advantage that substances can now beground which formerly could notbe submitted to a grinding process owing to. their toughnes's. In combination with the working method of this invention the application of extreme temperatures, known per se, may be advantageously used in some cases for increasing the fineness of the goods, thus allowin to improve the results which is obtaine by the simple grinding process.

Owing to the application of pressure it is of course necessary that all the'chambers of the grinding machine through which the goods are moved to the grinding surfaces, be made pressure-proof and tight at their joints. If an additional pressure medium is applied, all joints must also be made tight against the action of this medium. As the mass passes under pressure between the grinding surfaces, the total section available between these surfaces is continuously utilized so that with a given area of these surfaces the out-put is considerably increased.

Furthermore 'it is possible to carry the grinding process beyond the usual limit, that is to say to work with grinding surfaces arranged at a much smaller distance than usual, so that the final product will be of a grain considerably finer than hitherto obtained.

The increased rinding action performed on the same grin ing surface will, however, generate a' far greater amount of heat which i may render indispensable the use of a more efficient cooling device than hitherto required. I have, therefore, provided a cool-- P ing system not only for the hood but also for the grinding surface.

The increased grinding output obtained by the use of pressure renders it advisable to provide an automatic or semi-automatic feed of the mass to be conveyed to the grinding device in order to fully utilize its higher working capacity. This detail is of special importance in view of the fact that the admission of the mass when changing the storage tanks must be controlled i. e. started and interrupted in a redetermined order simultaneously with t e operation of valves and gates for the mass and the device influencing or governing the pressure effect or the admission of the pressure medium. In case of a simple non-automatic hand feed it is necessary to shut the admission pipe of the pressure medium before opening the storage tank and introducing the goods to be ground and to re-open it after the goods have been introduced.

The storage tanks arranged at the top of the grinder through which the goods are to be conveyed under pressure according to this invention, will suitabl be furnished with a stirring or mixing evice; they are made readily exchangeable and tightened by joining surfaces to similar surfaces on the grinding device with or without interposed packing means. In order to empty the tanks as completely as possible before exchanging same, the mixer should be so shaped as to assure also a thorough emptying of the storage tanks.

If it is desired to maintain the goods at a higher or lower than normal temperature while the pass through the tank or the grindera nown device may be arranged for this purpose.

An embodiment of a grinding device according to my invention is illustrated by way of example in the accompanying drawings. Fig. 1 shows the grinding device in front view with a storage tank placed on top and a pressure generating device actuated from the driving shaft. The grinding goods are fed by means of compressed air. Fi 2 gives a section through the same grin ing evice perpendicularly to the plane of Fig. 1. The drive and the pressure generating device are arranged behind the grinding device. e

The grinding mechanism according to- Fig. 2 is the following: In the casing base 1 there is located a step-bearing 2 for the vertical main shaft 3 driven by means of a bevel gear wheel 4 from a horizontal main driving shaft. The step bearing 2 may be raised or lowered by means of a screw 5 actuated by a hand wheel 6, whereby the degree of grindmg fineness may be adJusted as desired. The hood 7 provided in a well known manner with a water cooling system 8 is placed on the casing base 1. The grinding cone 9 fixed to through a bore 12 of the shaft 3 and through the outlets 11 into the hollow room against the inner walls of the conical surface. In order to assure a thorough cooling effect the water is kept close to the cone by means of a baflie plate 13 and collects in an annular channel 14 in the interior of the grinding cone, whence it flows through the outlets 15 into a tank 16 shaped like the frustrum of a cone surrounding the shaft. Thence the water is drained oil through a tube.

The hood carries the upper part of the casing 17 forming the pressure room and the storage room. This room is traversed by the main shaft 3 to which the mixing device 18 may be attached. It is closed by a strong and pressure-tight cover 20 which is also traversed by the main shaft, a stufiing box 19 securing a tight fit. The cover is provided with asmaller opening closed by a cover 21 also well tightened, placed in Fig. 1 behind the branch of the storage tank and with a connection leading to compressed air pipe 31. A storage tank 23 also fitted-with a mixing device 22 for the introduction of the goods to 'be ground fnay be directly connected to the opening 24 of the cover by means of the branch 25, whilst the mixing shaft 26 of this storage tank extending below may be connected by means of a coupling flange 27 to a coupling flange 28 fixed'to the main shaft 3 protrudlng through the cover and thus be entrained by the main drive. The opening for introducing the goods into the storage tank placed on top of the grinding device may be closed by a cover 29. 30 is the connection to the pressure pipe 31, leading to the press or pump 32 not visible in Fig. 2 but shown in Fig. 1 near the drive. 4

f the grinding machine is fitted with a hand feeding device only it is necessary, in order to revent the air or any other pressure medium om escaping, first to close the pressure pipe 31 by cutting in a shut off member not shown in the drawing; then the cover 29 is opened, the goods are introduced and the cover 29 is shut again-4, whereupon the shut off device for the admission of the compressed air is re-opened.

What I claim is:

l. A grinding machine having an upper, conical grinding element and a lower, complementary conical, hollow grinding member, a hollow shaft on which the latter member is mounted, outlets from the shaft within the hollow member, a bafileplate to direct cooling water in a sheet close to the under .from said chamber, a detach surface thereof, and an overflow between the baflle and the lower part of the hollow member and means to receive and discharge the cooling water. 7

v 2. In a grindin machine for pulpy material to begroun under pressure, a casm a grinding member and a cooperat grin ing member therein, a shaft on :fich the latter member is mounted and extending through the casing, a removable storage tank connected to the casing, a detachable shaft extension in the storage tank, a scraper on the shaft and on the extension, and means to supply pressure medium to both tank and casing.

3. In a grinding machine 'for pulpy material, a closed ressure chamber, cooperating grinding members with opposite grindin surfaces to which material to be ound is fe a 1e and exchangeable storage chamber, means to establish communication v between the latter and the closed chamber for discharging the material to be ground into the pressure chamber, means for supplying a pressure medium to both chambers, and means for controlling the supply of said medium, v p

In testimony that I claim the foregoing as my invention, I have (1 my name.

ALBERT. 

